In various manufacturing operations a plurality of elongated workpieces which may be solid or hollow are delivered to an input station in basically jumbled condition, with some of the workpieces overlying, and some underlying others. In order to act on the workpieces individually, for instance to saw them to length, they have to be sorted into an array extending generally parallel to one another with no workpiece lying underneath or atop another. This is a particular problem in a milling operations where the generally straight roundwood is dropped from a truck onto a chain conveyor, or in an industrial system cutting into sections long lengths of tubing or hose delivered in bundles which might actually be twisted.
In a trample-beam system there are a plurality of separately driven beams extending transverse to the workpieces and that basically repeatedly push down on them until the workpieces are only one layer thick. The movements of the various beams are synchronized, with the downward movement starting at one end and traveling longitudinally along the workpieces to hanmmer them into place. Obviously such a piece of equipment is very large and complex. Furthermore the vertical stroke of the trample beams must be carefully adjusted for maximum workpiece diameter. See German utility model 295 00 945.
Another system has a brush arrangement that rotates to brush back the workpieces in a direction opposite their displacement direction which, as usual, is transverse to the elongated workpieces. Thus any workpiece lying atop another is brushed back until it falls into place. The brush can travel along the workpieces to orient them as it travels.
In another system (U.S. Pat. No. 4,997,079) there is a roller provided above the transport surface which has wheel elements with grooves extending transverse to the transport direction. When driven against the movement direction of the workpieces these rollers again sort the workpieces into a generally parallel array. Conveyor belts (German 2,937,496) can also be used.
All these devices are quite complex, often require careful readjustment as workpiece size changes, and occasionally let two crossed workpieces get through to the downstream end of the input conveyor, where they are supposed to lie one deep and extend generally parallel to one another.